Bicycle propelling mechanism.



No. 632,536. Patentd Sept. 5, |399. E. B. PAnKHuRsT. BICYCLE PRPELLING MECHANISM.

(Application lcd July 5! 1898.)

2 Sheets-.Sheet (No Mudd.)

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No. 632,536. Patented Sept. 5, |899.

E. B. PARKHURST.

BICYCLE PROPELLING MECHANISM.

(Application filed July 5, 1898.)

(No Model.) 2 Sheets-Sheet 2.

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UNITED STATnS PATENT OFFICE.

EDIVARD B. PARKI-IURST, OF BOSTON, MASSACHUSETTS.

BICYCLE PROPELLING MECHANISIVI- SPECIFICATION forming para of Letters Patent No. 632,536, dated september 5, 189e. Application flled Inly 5, 1898. Serial No. 685,140. (No model.)

To all whom, it may concern:

Beit known that LEDWARD B. PARKHURST, of Boston, in the county of Suolk and State of Massachusetts, have invented certain new and usefulImprovements in Bicycle Propelling Mechanism, of which the following is a specification.

rlhis invention relates to the propulsion of bicycles and other wheeled vehicles, and has for its object to provide certain improvements in the propelling mechanism of the same whereby the speed of the vehicle may be decreased and the power multiplied, and vice versa, and whereby the crank-shaft may be entirely disconnected from the transmitting devices, so that the rider may coast without the revolution of the cranks. In other words, the object of the invention is to provide an improved change-speed mechanism" adapted for use on bicycles whereby the drivin g-wheel may be driven with a high gear on level roads and with a low gear7 when being propelled up a hill or incline.

To these ends the invention consists in certain improvements which I have illustrated upon the drawings and which I shall now proceed to describe in detail and finally point out in the claims hereunto appended.

Reference is to be had to the accompanying drawings, and to the letters and figures marked thereon, forming a part ofthis specification, the same letters and figures designating the same parts or features, as the case may be, wherever they occur.

Of the drawings, Figure l represents in side elevation a bicycle equipped with my invention. Fig. 2 represents in side elevation the casing and the change-speed gearing therein, one end of the casing being removed. Fig. 3 represents a plan view, partly in section, of the change-speed devices. Fig. 4 represents the same with the movable clutching member in a different position. Fig. 5 represents a section on the line 5 5 of Fig. l, the parts being greatly enlarged. Fig. 5f represents a sectional detail hereinafter referred to. Fig. 6 shows in detail the mechanism for effecting the movement of the sliding clutch member. Figs. 7 and 8 illustrate the invention applied to a vehicle driven by bevel-wheels from the crank-shaft, such a bicycle being commonly .known as chainless It will be understood that though I describe some features of my invention in connection with a bicycle I do not desire to be understood as limiting their application thereto, as they may be employed in mechanisms 0f other kinds for accomplishing a variation of the speed of the driven member relatively to the speed of the driving member. At the same time, however, the invention possesses certain features which are especially applicable toV bicycles, as I shall subsequently point out, and such features also form the subject-matter of some of the claims hereinafter presented.

Referring to the drawings,I have illustrated a bicycle which in Fig. l is portrayed as being provided with a sprocket wheel and chain for imparting motion to the rear wheel and in Figs. 7 and 8 as being equipped with bevelgearing for accomplishing the same purpose.

The crank-shaft ct is hollow and upon itsv ends are rigidly' secured the cranks a a. This shaft ct extends through a casing b, which in side elevation presents the appearance of two overlapping circles, as shown in Fig. 2. connected by brazing or otherwise to the bars 2, 3, and 4 of the bicycle, and in it are placed all the parts of which the speed mechanism is composed. The ends of the casing are closed by plates h b2, through which the shaft projects. The plate b2 is formed with `a socketed or concave portion b3, surrounded by the annular ribs or iian ges b, which form a groove The casing or hanger b is suitably b5 to receive the flanged rim of a washer or plate h6, between which and the concave portion b3 are placed antifriction-balls c. The washer or ball-retainer h6 is provided with a central aperture to receive the shaft a, and besides retaining the antifric tion-balls in position it prevents the entrance of dust to the interior of the casing, the balls c being inserted between the end plate h2 and the shaft tt to permit the shaft to rotate without friction. Upon the opposite end of the shaft ais loosely placed the sprocket CZ, ywhich is formed with an inwardly-projecting hubd, extending through the plate 1). The said plate b also has a cavity or concave portion 297 similar to that at b3, but greater in cross-diameter. Between the concave portion 297 and the sprocket-wheel b are placed antifriction-balls IOO c', and between the sprocket and the shaft ct are placed antifriction-balls c2, held against displacement by a ball-retainer bs, similar to that at 56. It will be observed that the plate b' is provided with a groove b9, into which an annular iiange d1" of the sprocket-wheel projects and that the sprocket-wheel itself is provided with an annular groove Zitoneceive the flanged rim of the ball-retainer (Z8.

Vithin the. casing a large gear e is rigidly secured to the shaft c, and it has a reduced toothed portion e', equal in diameter to a smaller gear f, rigidly secured to the hub CZ of the sprocket-wheel and mounted loosely on the shaft CL. The gearfis provided with a reduced end portion which projects into a cavity or socket e2 in the gear e and is provided at its ends with a cup to receive antifriction-balls c3, which are inserted between it and the shaft a in the gear e.

As thus far described, it is apparent that the crank-shaft a is mounted loosely in antifriction-bearings in the casing and that the sprocket-wheel and the gear f are likewise mounted upon antifriction-bearings on the crank-shaft. The reduced portion e of the gear e has the same number of teeth as the gear f, and they may be brought to register with those of the said gear f, as shown in Fig. 5.

Extending through the end plates h b2 of the casing is another shaft Zz', which is secured in place by a pin Zt'. Upon this shaft are loosely mounted two gears of different size rigidly secured together. The larger gear t is adapted to intermesh with either the gear for e', or both, while the smaller gearis adapted to intermesh only with the gear e. They are provided with telescoping flanges 17j', rigidly secured together by the screw i2, and they are socketed to receive antifriction-balls Zt,interposed between them and the shaft h and held against displacement by the retainingplates Zt" Za', secured to the gear by screws 7a2 7a2. When the gears are in the position shown in Fig. 5, the sprocket-wheel is disconnected from the shaft, and consequently the rider may keep his feet upon the pedals and coast without the cranks revolving. In Fig. 3 the gear-wheel is pictured as intermeshing with both the gear f and the toothed portionv c' of the gear e, and it will thus be seen that it acts to connect lthe two last-mentioned portions, whereby the sprocket-wheel is driven rotation for rotation by the crank-shaft, or, in other words,the sprocket-wheel and the crankshaft rotate at the same rate of speed. When, however, the gears i j are shifted to bring the gear j into mesh with the gear e, power is imparted from the crank-shaft to the gear f through the medium of gears e, j, and fi, and therefore the sprocket-wheel is driven at a higher rate of speed than the crank-shaft.

In order to shift the gearsz' and j, I employ a rock-shaft or rod Z, mounted at one end in a boss Z in the casing b and at its other end ina bracket Z2, projecting out from the saddlepost. The lower end of this rod projects through the said casing and is provided with an arm Z3, extending between the gears t' and j, whereby when the rod is rocked the gears are shifted.

To accomplish the rocking of the rod, it is provided with a handle Z4 on its upper end, which has a linger Z5, adapted to drop in either one of two notches Z6 Z7 in segmental arms Z8, carried by the` sprocket, and lock the gears ij against sliding movement. The handle Z4 is thus in a convenient position to be operated by the rider, who can do so without dismounting.

In order to adjust the shaft ct and the parts thereon, it is provided on its ends outside the ball-retainers b ha with elongated slots a2 to receive cross-pins co3, which bear against the said ball-retainers, as shown in Fig. 5. The ends of the hollow shaft ct are internally threaded and screws a4 are screwed thereinto until their ends bear against the cross-pins as. By adjusting the screws CL4 the shaft may be moved longitudinally, as will be readily understood. The shaft h is not adjustable, there being no necessity for this, but it is closed by a screw a4.

In order to provide a sufficient supply of lubricant, the hollow shafts are filled with it and are provided with ducts a5 and h2, whereby it is adaptedto flow outward to therantifriction-balls, the gears, and the other moving parts.

In Fig 5 one of the screws a4 is shown as having a through-aperture, whereby lubricant can be injected through it into the crank; shaft without aecting the adjustment of the parts thereon. In this event the screw is comparatively short'and a screw-cap a15 is driven in after it to close the aperture therethrough.

The adjustment of the various parts on the crank-shaft is readily accomplished by turning one of the screws a2, which causes the parts to approachtoward or recede from each other.

The casing is practically dust-proof, since Vit is practically impossible for foreign matter to find its way between the ball-retainer and IOO IIO

the sprocket and the vsprocket and plate b' on the one end and the ball-retainer and the plate b2 on the other end, by reason of the parts having practically tongue-and-groove connections.

While I have described the gear-wheel e as having a reduced portion e, it will be understood that I include thereby a gear, such as e, anda separately-formed'small gear equal in diameter or number of teeth to the gear f and rigidly secured either to the gear e orto the shaft a.

The gear t' is continuously in engagement with the gear f, and it operates either as a clutch to connect the gears f and c or else as a member of a train of gears for multiplying the speed of rotation.

I have contemplated the employment of mechanism for accomplishing three variations in speed of the toothed wheel-i. e., the sprocket or bevel wheel-and consequently do not limit my invention to the exact number or construction of the parts shown.

Having thus explained the nature of the in.- vention and described a way of constructing and using the same, though without attempting to set forth all of the forms in which it may be made or all of the modes of its use, I declare that what I claim isl. A change-speed device, comprising a driving-shaft, a second shaft parallel thereto7 two gears on the driving-shaft which are different in diameter, two gears of different diameters on the said second shaft, the gears on one of said shafts being slidably mounted thereon and the construction being such that one of the gears on the second shaft may lock or clutch together the two gears on the driving-shaft by said sliding, and means for shifting the said slidably-mounted gears.

2. A change-speed device for bicycles, comprising a driving-shaft, a second shaft parallel thereto, two disconnected gears on the driving-shaft of which one is larger than the other and is provided with a reduced tooth portion equal in diameter to the other, connected gears slidably mounted on the other shaft, of which 'one gear is adapted to intermesh with the smaller of the first-mentioned gears alone or with it and with the reduced toothed portion of the larger gear, and the.

other is adapted to intermesh only with the larger of said gears, and mechanism for longitudinally sliding said connected gears.

3. Bicycle propelling mechanism, comprising a crank-shaft, a toothed wheel loose on said shaft, a small gear loose on said shaft and connected to the toothed wheel to turn therewith, a large gear rigidly secured on said shaft and having a reduced toothed portion equal in diameter to the small gear, a second shaft, two connected gears loosely mounted to slide on said shaft, one of said gears being adapted to engage the first-mentioned small gear alone or to engage it simultaneousl7 with the reduced portion of the large gear, and the other of said gears being adapted to engage the large gear, and mechanism for shifting the said connected gears.

4. Bicycle propelling mechanism comprising a casing, a crank-shaft jonrnaled in said casing, a supplemental shaft mounted in said casing, a toothed wheel loose on one of the shafts outside of the casing, a set of disconnected large andsmall gears on the last said shaft, one of said gears being connected to the toothed wheel and the other to the shaft, a set of connected large and small gears on the other shaft, and adapted to engage the first said gears, one of the gears on the supplemental shaft being arranged to either engage only one of the gears on the crank-shaft or to lock or clutch both of the crank-shaft gears together and mechanism for shifting the said connected gears to vary the speed of rotation of the said toothed wheel.

5. Bicycle propelling mechanism comprising a casing, a crank-shaft journaled in said casing, a supplemental shaft mounted in said casing, a toothed wheel loose on the crankshaft outside the casing, a set of disconnected large and small gears on the crank-shaft, one of said gears being connected to the toothed wheel and the other being connected to the crank-shaft, loosely-sliding connected large and small gears on the supplemental shaft and adapted to intermesh with the first-m entioned gears, one ofthe gears on the supplemental shaft being arranged to either engage only one of the gears on the crank-shaft or to lock or clutch both of the crank-shaft gears together, and mechanism for sliding the said connected gears, for varying the speed of the said toothed wheel, or disconnecting it from the crank-shaft.

6. A bicycle propelling mechanism comprising a crank-shaft, a supplemental shaft, a toothed wheel on one of said shafts, a set of large and small toothed gears on each of said shafts, one of the gears of one set being continuously intermeshed with one of the gears of the other set, mechanism for shifting one set of said gears including one of the continuously-meshed pair, and means whereby the non-shifting gears on one of the shafts may be locked together or released from each other by shifting the movable set of gears on the other shaft.

7 Bicycle propelling'mechanism comprising a shaft, a toothed wheel, antifriction devices between the toothed wheel and the shaft, a casing, antifriction devices between the shaft and the casing, and means for simultaneously adjusting all of said parts.

8. lBicycle propelling mechanism comprising a shaft, a toothed wheel loose on the shaft, a gear rigid on the shaft, antifriction devices between the toothed Wheel, the shaft and the gear, a casing, antifriction devices between the casing and the shaft, and means for simultaneously effecting an adj-ustment of all of said parts.

In testimony whereof I have afxed my signature in presence of two witnesses.

EDVARD B. PARKHURST.

vWitnesses:

A. D. HARRISON, H. L. RoBBrNs.

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